Process for the separation of ammonia from its formative gases



Dec. 9, 1924. 1,518,421

W. T. WAKEFORD PROCESS FOR THE SEPARATION OFANMONIA FROM ITS FORMATIVE GASES` Filed Feb, 27, 1922 60 uniform conditions of WmLIAM T. vvvalinroao, or rnovmnncn,

aan conroaa'rIoN, or raovrnnncn, cnn ISLAND, asc

ISLAND.

rnoeEss :son THE SEPARATION or ons isteria, .L enea 'ro ntoma nnen: irs ro esem Application filled February 27, 1922. Serial No. 539,855.

' To all 'whom tpmag/ concern:

Be it known that I, WILmAM T. WAKE- -Fonn, -a citizen of the United States, residing at Providence, in the county of Providence and Stateof Rhode Island, have invented catalytic agent to form ammonia and separating the ammonia thus formed from the residual gases to secure a product of great purity with la minimum expenditure of time and labor.

One object .of the invention'is to provide an improved method of operation whereby the .ammonia formed by contacting a nitro! gen-hydrogen mixture with. a catalytic agent may be removed' from the residual gases Without materially reducing the pressure in the main circulatory s m and at the same time a fresh supply of the mixture of nitrogen and hydrogen constantly added under pressure to the gases remaining after the removal of the ammonia content therefrom thus avoiding the necessity of raising the pressure of the mass of circulatory gas after each removal 'of the ammonia content and economizing time and labor.

Another object of the invention is 'to provide'a convenient'means for separating the ammonia content fromv the gases emergin from the synthesizing chamber by expan ing a portion -`of the liquid ammonia formed as a result of the synthesis and utilizing the ending" ammonia to liquify the comgases. while ,at the same time recovering the expanded ammonia and returning the same to the system for liquefaction.

A further objpctvof the invention is the provision of an improved apparatus of the characterdescribed comprising a circulatory system whereby constant circulation of the gases 'may be effected under substantially other objects and of sie im vention relate to certain improved steps and combinations of 'steps aswell as certain im proved details of construction and arrangement of the parts as will -be more fully set forth in the detailed description to follow.

in the annexed drawings Fig. 1 is a diagrammatic illustration of one form of apparatus which may be advantageously employed in carrying out thefimproved process certain portions thereof being shown in section to better illustrate the details of construction and method of operation, and Fig. 21s a sectional vlew of a portion of the liquefying coil vtaken along the line 2.-2. of

eferring to the drawings 1 designates the. contact chamber of an onia s thesis apparatus within which is placed t catalyticagent for forming ammonia from the nitrogen-hydrogen mixture, the gases to be synthesized entering the chamber l through the pipe 2 to which. they are supplied through a pipe 3 leading from'fa compressor 4 in which they are placed under the requi# site pressure after having been drawn Jfrom 'asuitable source of supply. After having passed into contact with the hot catalytic agent in the chamber 1, the gases' pass therefrom through the pipe 5 and into the intermediate passage 7 of a coil 9 enclosed in a casing 10.

The coil 9 includes a plurality of concentric tubes, in the present instance, three in number, which are positioned one within another and preferably surrounded by a heat insulating material 11 such as cork or the like. The coil may be of any desired length to best accomplish the coolin yof the gases entering from the contact c amber, and the coil 9 taken in conjunction with the receptacle 12 and their connecting municates with! the interior of t e rece tacle v by'means of a connecting pipe 17 al ou h. connection with the receptacle ma be ma e by prolonging' the tube 14 Within the re-` ceptacle instead of employing the connectin pipe 17. ln any event however the pipe 1 passages 6, 7- and 8 respectively. l

Mld

l l a closed-circulatory or that portion ci the tube 14 which may project withinthe rece tacle 12 terminates substantially midway tween the bottom and top of the receptacle and slightly above the open end 18 of a pi 19 entering the base of the receptacle 12j. us as the gases entering the coil 9 from the contact 'chamber are cooled in passing' downwardly throu h the passage 7 the ammonia contentof t e gases is liquefied and passes into the recep-v tacle 12 and accumulates therein until t e level of the liquid ammonia reachesthe open end 18 of the pipe 19 when the surplus ammonia may be removedby opening the valve 20 in the pipe .19 and placed in a suitable tank or container. The residual uncombined nitrogen and hydro en gases entering the receptacle 12 through t e pipe 17 fills the upper portion of the receptacle and may pass outthrough the pipe 22 into the passage 8 within the outer tube 15 of the coil whereupon it passes upwardly throu h the coil 9 and enters the pipe 23 from w ich it passes to the circulating pump 24 and is thereby forced forward through the pipe 2 into the contact chamber for further synthesis. The outer tube 15 of the coil may be extended downwardly into the receptacle 12 instead of making use ofthe connecting pipe' 22 as shown, but in either case the` tube 15 or the connecting pipe 22 referablyterminates above the vopen end o the tube 14 or itsmequivalent pipe 17 in order to better facilitate the proper-circulation of the gases throughout t e main circulatory system. The main circulatory system comprises the ycontact chamber 1, pipe- 5tube 14 and connection 17 to the receptacle, as well as ,the connection 22, the tube 15, pipe 23, circulating pump 24 and pipe 2 from the pum to the contact chamber thus forming in e ect f wherein the mixture o nitrogen an y ro n me into' contact with a catalytieagent inptl contact chamber and from there to `the liqueer for the removal of the ammonia formed and thence through the circulating pump to thel contact chamber whereby repeated synthesis of the nitrogen and hydrogen is effected a fresh suppl of the'nitrogen-hydrogen mixture being ed into the system from thepipe3 asmayberequiredto replace the gasesremoved in thevformation of ammoma.l l

The inner tube 13 of the coil 9 extends into the receptacle-12 and terminates atl a point 30 adjacent to the bottom ofthe v tacle .and below the normal level 310i t e liquid ammonia in the rece le. A valve 32 located in the tube 13 above the rece tacle 12 may be opened to permit the iquid v ammonia contained in the receptacle to expand into the p 6 and thus absorb heat to cool the gases from the contact chamber in the passage 7 for the purpose of liquefynatanti panded ammonia passes from the tube 13 at the topv of the coil into a pipe 33 from which i it passes to a trap 34 for the purpose of re-A moving any ammoniawhich may be present therein in the liquid state. From the trap 34 the ammonia is conducted to a separate compressor 35 through a pipe 36 where the gas is'placed under a pressure substantially ual to that in the main circulatory system w ien the gas is forced back into the main circulatory system through the pipe 37 to enter the main system between the contact chamber and liqueiier and pass with the gases from the contact chamber-through the passage 7 in the coil to liquefy the ammonia.

The pressure in the main circulatory system is substantially constant throughout the system being only slightly lowered vby the removal oi the ammonia content of the gases in the. passage 7 and this slightllowering of the pressure is made up by the addition of a fresh nitrogen 'and hydrogen mixture from the compressor 4, while the .gases are constantly circulated through the system by means of the circulatory pump A' pipe 38 provided with a valve 39-serves t^ permit the removal oil any liquid ammonia which may accumulate inthe-trap 34. vThe various joints between the several pipes andA other elements of theapparatus may be made by welding to prevent the possibility Y of gases escaping at these points, and the tubes 13, 14 and 15 are 'preferably joined to 'each' other at the ends of the coil 9- by welding. The ammonia expanded in the tube 13 to cool the gases from the contact chamber sufiiciently lto liquey the ammonia turned to -the pressure of the'main circulatory system by means of the separate' compressor 35 with the expenditure of a relatively small amount contained therein .can be re of power `and the provision of thisfseparate compressor andthe shunt circuit formed of the tuhe13 pipe '33, trap 34, pipe 36 'comuncombined as they emerge from the contact chamberby expanding a portion of the liquefied ammonia vout of contact with the residual gases and in. heat exchangm' relation with the gases from the contac chamber.

This is'accomplished in a .shunt 'circuit thus permitting the maintenance of the pm `ll0 presser I35 and pipe 37 avoids the necessityl retener sure substantially uniform in the main circulatory system, and the ammonia thus eX- panded is readily compressed and returned to the system for removal together With the ammonia formed in the Contact chamber. The pressure throughout the main circulatory system may be maintained at the point best -adapted' to further the synthetic production of ammonia in the contact chamber such, for example as eighty to one hundred and fifty atmospheres, ydepending upon the catalytic agent employed and the conditions of'operation.

What li claim is:

l. lin a process for separating synthetic ammonia from its formative gases 'in a closed system Which. includes a main synthesizing circuit and a shuntcircuit, the steps comprising, separating a portion of the ammonia from its formative gases by liquefaction, returning the residual gases for retraversement of the main circuit, and expanding a portion of the liquid ammonia in a shunt circuit to cool a fresh supply of gases.

2. ln a process for separating synthetic ammonia from its formative gases in a closed system, the steps comprising separating the ammonia formed between each passage of the formative g'ases through the system by liquefaction While maintaining the gases under substantiallyuniform ressure, and expanding a portion of the liquid ammonia to cool a fresh su ply of gases and eHect the liquefaction of the ammonia content therefrom.

3. fn a process for separating synthetic ammonia from its formative gases in a closed system which includes a main circuit and a shunt circuit, the steps comprising separating the ammonia formed between each passage of the gases through the system by liquefaction While maintaining the gases under substantially uniform pressure, expanding a portion of the liquid ammonia in the shunt circuit to eect liquefaction of the ammonia from a fresh supply of gases, compressing said expanded ammonia, rand returning the same to the main circuit.

4. lin a process for separating synthetic ammonia from its formative gases in a closed system which includes Ia main synthesizing circuit and a shunt circuit the steps comprising, separating a portion of the ammonia from its formative gases hy liquefaction', returning the residual gases for retraversement of the main circuit, expanding a portion of the liquid ammonia in a shunt circuit to cool a fresh supply of gases, compressing said expanded ammonia in the shunt circuit and returning the same to the main circuit.

In testimony whereof l have axed my signature.

man r. Wannronn. 

